JPS63209725A - Method and apparatus for performing local ventilation and dust removal - Google Patents

Abstract

PURPOSE:To perform high-efficiency local ventilation and dust removal by sucking air contaminated with dust by means of Coanda spiral flow formed by feed of pressurized fluid and carrying it through a dust and removing it. CONSTITUTION:In a method for performing local ventilation and dust removal of a tunnel or the like, a Coanda spiral flow producer 1 is connected with a duct 2 and pressurized fluid is sent to a cylindrical pipe 3 through an introduction pipe 4. Further a wall face 6 smoothly bent toward the duct 2 from an annular slit 5 is provided and a bent wall face 7 is provided to the opposite side. When introducing fluid through an introduction port 9, the movement vector of pressurized fluid fed through the slit 5 and the movement vector of fluid introduced through the introduction port 9 are synthesized and spiral motion 10 is caused. In this case, the pressurized fluid is transferred while drawing a flow line shown in an arrow alpha by Coanda effect in the outlet of the slit 5 and a movable boundary layer is formed in the vicinity of the inner wall face of the dust. By such a way, local ventilation and dust removal can be performed with a miniaturized apparatus with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a local ventilation/dust removal method and apparatus. More specifically, the present invention relates to a method and apparatus for effectively ventilating and removing dust in areas such as tunnels, construction sites, factories, etc., where air pollution by dust is significant.

(Background technology) Conventionally, large fans have been commonly used to ventilate and remove dust from confined spaces such as tunnels, construction sites, and factories where there is significant dust pollution. .

Depending on this method, the fan's ventilation and dust removal capabilities are not very large, and the power required is large, resulting in a considerable cost burden. Air pollution caused by dust cannot be effectively suppressed by such methods using fans, and urgent measures are needed from the health and safety of workers.

In recent years, in order to deal with such issues,
A method of forcibly suctioning and removing dust-contaminated air using pressurized air has been proposed, and devices for this purpose have also been put into practical use.

The device shown in Figure 7 is an example of this, in which a pressurized air inlet slit (A) is provided near the suction port (A), and the pressurized air is distributed toward the exhaust port (X). By doing so, dust air is sucked in from the suction port (A) and forcibly exhausted. This device uses 1 as pressurized air.
Air pressurized to ~7 kg/ci is fed into the slint (
(a) and removes dust-contaminated air using a jet flow.

FIG. 8 shows an example of use in a tunnel cleaning system. Air contaminated with dust is blown backwards by this jet flow generating device (1), and is purified (specifically treated) by a dust collector (power) through a duct (o).

In the case of jet flow devices and dust removal methods that use them, which have already been proposed and put into practical use, ventilation and dust removal in local areas such as tunnel faces are far more efficient than when using fan methods. Although this can be done efficiently using small equipment, there are still issues to be overcome.

In other words, in the method using this jet flow device, as is clear from FIG. The velocity at the center is the highest, and the velocity at the center is low, resulting in an extremely large air pressure drop, which greatly limits the ability to eject dust. The distance that dust is blown out from the exhaust port is only about 20 meters at most, and air contaminated with dust will be released into spaces beyond this distance, as shown in Figure 8. Become. Recovery into the duct (O) is only limited. In order to increase the collection by this tough) and (e), it is necessary to make the dust collector 11 even larger.

It is also conceivable to connect the discharge port (1) and the duct (O) with a conduit. However, in the case of this jet flow device, since the velocity near the inner wall surface is high due to its structure, dust tends to adhere to the pipe wall, and the wall surface is worn out by contact with the g-wall. For this reason, the actual situation is that pipes cannot be used.

In either case, a large-sized dust collector is required for collection, and the cost of installing and operating it is also large.

Therefore, in place of the conventional methods and devices described above,
There has been a strong desire to develop a local ventilation/dust removal method and equipment that can be operated at low cost using highly efficient and compact equipment.

(Objective of the Invention) This invention was made in view of the above circumstances, and provides a new, more efficient local ventilation/dust removal method and device for the same, which improves the shortcomings of conventional methods, devices, and devices. is intended to provide.

(Disclosure of the Invention) The local ventilation/dust removal method of the present invention is characterized by: ``Dust-contaminated air is suctioned by a Coanda spiral flow generated by supplying a pressurized fluid, and one shell is removed through a pipe. .

The local ventilation/dust removal device of the present invention also includes a Coanda spiral flow generation device that sucks and conveys dust-contaminated air;
It is characterized by consisting of a conduit for transporting dust-contaminated air, and a dust collecting water tank or a dust collecting shower device connected to the conduit.

Coanda spiral flow is the traditional fluid luck! It is completely different from laminar or turbulent flow, which is known as the ll concept.
This was discovered by the inventor of the present invention as something that is different from turbulent flow even though it is under a fluid motion condition that belongs to a turbulent flow region. Its generation has already been proposed by this inventor.

In other words, the inventor of this invention discovered that when a vector in the radial direction of the tube is added to the vector of fluid in the direction of the tube, the fluid swirls, a dynamic boundary layer is formed near the inner wall of the tube based on this swirling flow, and the fluid spirals. In such a Coanda spiral flow, the fluid moves at high speed and, due to the presence of a dynamic boundary layer, solid particles are present. Unlike in the case of turbulent flow, the fluid does not collide with the inner wall of the pipe. Therefore, during the process of fluid spiral motion, the fluid maintains a uniform state, and local deterioration due to collisions and contact with the inner wall is suppressed υ1 be done. Wear on the inner wall of the tube is also controlled.

These excellent properties are extremely useful for transporting fluids such as powder, slurry, and fibrous materials, as well as for chemical and physical unit processes and their systems.

The inventor of the present invention has already proposed, for example, a device as shown in FIG. 1 of the attached drawings for generating Coanda spiral flow having such excellent features.

In the example shown in FIG. 1, the Coanda spiral flow generating device 1 is connected to a pipe line 2, and a cylindrical pipe 3 connected to this pipe line 2 has a diameter that gradually increases in the opposite direction. A pressurized fluid, for example a compressed flow of gas, air or liquid, is fed into the cylindrical tube 3 from the side through an inlet tube 4. An annular slit 5 is provided to feed this pressurized fluid in the direction of the pipe line 2 . Further, from this slit 5, a smoothly curved wall surface 6 is formed toward the pipe line 2.

A bent wall surface 7 bent at a right angle or an acute angle is provided on the side opposite to the curved wall surface 6. The interval between the slits 5 can be freely adjusted. Furthermore, a distribution chamber 8 is provided for uniformly supplying pressurized fluid to the slit 5.

The end face opposite to the pipe line 2 is an inlet 9, through which fluid can be introduced.

In the Coanda spiral flow generation device having such a structure, the motion vector of the pressurized fluid from the slit 5 and the motion vector of the fluid from the inlet 9 are combined to generate a spiral motion 10. At that time, slit 5
At the outlet of the pipe, the pressurized fluid moves along the streamline shown by the arrow α due to the Coanda effect, forming a dynamic boundary layer near the inner wall surface of the pipe. Further, a large negative pressure area is generated on the side of the inlet 9 of the slit 5, which promotes the inflow of fluid from the inlet 9.

The shape of the vicinity of the slit 5 of such a Coanda spiral flow generation device is not limited to that shown in FIG. 1, but is, for example, as shown in FIGS. As shown, various shapes can be used. The slit 5 may be formed by a smooth curved wall surface 6 and a right-angled or acute-angled bent wall surface 7 so that the pressurized fluid flows from the slit 5 drawing a streamline α.

This invention performs local ventilation and dust removal using the above Coanda spiral flow generation device.

As shown in FIG. 6, the method and apparatus of the present invention include:
For example, the Coanda spiral flow generation device 11,
It consists of a pipe line 12 connected to this device, and a dust collection water tank 13 further connected to this pipe line. It is possible to transport long distances at high speed, and the length of the pipe line 12 is several tens of meters to twenty meters.
It can be installed up to about 0m. The pressurized fluid, for example pressurized air, is supplied from the pressurized air inlet 14 of the Coanda spiral flow generator 11 at a rate of 1 kg/- to 10 kg/a#.
Send within the range of . Of course, there are no particular limitations on this pressure.

Dust is sucked through the inlet 15.

The dust collection tank (13) can have an extremely simple configuration. This dust collection tank can be of various types and structures, and may be collected using a single shower system.
There is no need for a large collector like in the conventional method.

Coanda Spiral This is achieved by efficient suction and conveyance at a high flow rate of 20 to 120+1/S.

The Coanda spiral flow generator can be installed near the concrete spraying robot's spray nozzle, tunnel excavation machine, etc. There are no restrictions on its usage,
It can be selected as appropriate.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a Coanda spiral flow generation device of the present invention. Figure 2, Figure 3, Figure 4
FIG. 5 is a partial cross-sectional view showing an example of the slit portion of this device. FIG. 6 is a sectional view showing an example of the device of the present invention. FIGS. 7 and 8 are a sectional view and a front view of a conventional device. The numbers in the figure indicate the following. 1...Coanda spiral flow generation device 2...Pipe line 3...Cylindrical tube 4...Introduction pipe 5...Slit 6...Curved wall surface 7...Bend wall surface 8...Distribution Chamber 9...Inlet 10...Spiral motion 11...Coanda spiral flow generation device 12...
・Pipe line 13... Dust collecting tank 14... Pressurized air inlet 15... Inlet agent Toshio Nishizawa, patent attorney Figure 1↓ Figure 2 Figure 3 Figure 4 Figure 5
7 Artwork Figure 8

Claims (3)

[Claims] (1) A local ventilation/dust removal method characterized by sucking dust-contaminated air using a Coanda spiral flow generated by supplying a pressurized fluid and transporting and removing it through a pipe. (2) Local ventilation characterized by comprising a Coanda spiral flow generation device that sucks and conveys dust-contaminated air, a conveyance pipe for dust-contaminated air, and a dust collection tank or dust collection shower connected to the pipe.・Dust removal equipment. (3) The local ventilation/dust removal device according to claim (2), wherein a Coanda spiral flow generation device for sucking and conveying dust-contaminated air is installed near the spray nozzle of a concrete spraying robot.